PHP (PHPMailer)

Before you start

• PHP 7.4 or later
• phpmailer/phpmailer

1Install PHPMailer

composer require phpmailer/phpmailer

2Send a test message

<?php

use PHPMailer\PHPMailer\PHPMailer;

require 'vendor/autoload.php';

$mail = new PHPMailer(true);
$mail->isSMTP();
$mail->Host = 'smtp.mailclutch.com';
$mail->Port = 587;
$mail->SMTPAuth = true;
$mail->Username = 'mc_0000000000000000';
$mail->Password = 'pw_0000000000000000';
$mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;

$mail->setFrom('staging@example.com');
$mail->addAddress('anyone@example.com');
$mail->Subject = 'Sandbox check';
$mail->isHTML(true);
$mail->Body = '<h1>Hello from PHP</h1>';

$mail->send();

Watch it land

Open the sandbox and the message is there — rendered HTML, plain text, raw source, attachments, and the SPF, DKIM and DMARC verdicts. It updates live, so you can leave it open next to your terminal.

Nothing is ever delivered onward, whatever address you send to; claim the inbox with an account and it stays.

What usually goes wrong

• mail() cannot be pointed here

  PHP's mail() hands the message to a local binary, which has no idea about SMTP credentials. Either send through PHPMailer or Symfony Mailer, or relay the local MTA — see the Postfix guide.

• Debugging a refused connection

  $mail->SMTPDebug = 2; prints the whole conversation, which usually names the problem on the first line.

Other stacks

The same four values in another dialect. Every guide below is filled in with the sandbox pair at the top of this page.